Radio signaling system



i] 12 1927. Apr G. H. CLARK RADIO SIGNALING SYSTEM Filed June 27. 19 22 anoanto'c cz'oas: u. CLARK ya/m as, his aum Patented Apr. 12, 1927.

"UNITED STATES "PATENT OlF'lFlClEl.

GEORGE H. CLARK, OF BROOKLYN, NEW YORK, AS$IGNOR TO RADIO COBPORATEON OF AMERICA, A GORPORATION OF DELAWARE.

name SIGNALING SYSTEM.

Application filed. June 27,

The present invention relates to radio signaling systems in which the same antenna is used for transmitting and receiv1ngmessages.

In systems operating in this manner the reception is done through the antenna inductance ot the transmitter. lVhen the antenna is transmitting on long wave lengths it is then impossible to receive efficiently on short waves with the usual change-over systems. 7

The principal object of the present in vention is to eliminate this defect.

The novel features which I believe to be characteristic of my invention are particularly set-forth in the appended claims, the invention itself, however, both as to its construction and mode of operation, together with further objects and advantages thereof will best be understood by reference to the following description taken in connection with the accompanying drawing in which the single iigure diagrammatically illustrates an embodiment of my invention.

In accordance with an important feature of the invention the antenna inductance of the transmitter is cut out during receivin This is preferably done by short circuiting and simultaneously inserting the optimum inductance and capacity so that receiving at the desired wave length may be efliciently done regardless of the transmitting wave length.

In the embodiment of the invention illustrated in the drawing, 1 represents an antenna grounded at 2. A transmitting inductance 3, which may be adapted for transmitting relatively long wave length is included in the ground connection. The transmitter may be of any suitable type, but for purpose of illustration a quenched gap transmitter is shown comprising a source of power e connected through a transformer 5 to a quenched spark gap 6 connected-to an oscillation circuit comprising a capacity 7 and an inductance 8 coupled tot-he transmitting inductance 8.

The receiving circuit which may be {or hort waves while the transmitter may be for long waves is also connected between the antenna and ground. The receiver comprises, for. example, an inductance 9 and a varable condenser 10 of such constants that it ill eiiiciently receive the desired "waves 1922-. Serial no. 571,247.

regardless-of the value of the transmitting inductance. The receiving circuit comprising the inductance 11 coupled to the receiving coil 9 and tuning condenser 12 is connected to an indicating instrument such as a telephone 13 shunted by a condenser 14:

and a detector 15 in a well known manner.

ll henever the transmitter is not working the transmitting inductance will be automatically cut out and the receiver con nected in the aerial by suitable cooperating electrical and mechanical means. The illust-ration shown in the diagram utilizes a plurality of circuit interrupter 16 connected in series across the inductance 3. The contacts ot' the interrupter are separated to remove the short circuit by moving a longitudinally slidable shaft 17 to which one set of contacts 18 are mechanically connected.

The sl'idable shaft 17 is connected to an arm 4 attached to the arm 18 the movable armature 19 of an electromagnet 20 having its winding connected to a battery 21 and transmitting key 22. Cooperating with one end of the armature 19'is an insulated contact 23 which cooperates with contact 24 to open and close the circuit of the generator 4. At the other end of the armature a conducting member 25 is connected which is adapted to short circuit contacts. 26 and 27 which are connected across the receiving circuit 9, 10.

The detector 15 is also automatically disconnected t'roin the receiving circuit by the movement'of an extension 28 of arm 18 which is adapted to close contacts 29, 30 ot' a circuit connected to a battery 31 and electromagnet 32., An armature 33 of the electromagnet is slidably mounted in bearings and provided .with contacts 34, 35 connected to the detector 15 which cooperate with contacts 36, 37, to place the detector in the indicating circuit.

The operation of the arrangement is as follows:

lVith the transmitting key 22 open as shown, the apparatus is in condition to receive. The oscillations received by the antenna 1 pass through the series of interrupter-s 16 which are now short cireuited through. the receiving coil 9 and condenser 10, to ground without passing through the transmitting inductance 3 which is short circuited by the closed interrupters 16. Any tuning may :be selected for the receiving coil 9 as the transmitter inductance is out of the circuit. In the position shown contacts 29, 30 are open and the magnet 32 do energized so that springs 35% draw the armature 33 and. contacts 3-41,, 35 to connect the detector to the tuned receiving circuit 11, 12 and the telephone 13, which indicates the received signals in the usual manner. This arrangement is suited for reception of modulated waves, but obviously any known receiving circuit for continuous waves may be used without departing from the invention.

Transmission of signals occurs in the ifollowing manner by opening and closing the key 22. When the key is closed the electro magnet is energized and the core 19 moved to the left. This brings about the following: a closure of contacts 29, and energization of magnet 32 which attracts armature 33 and separates the contacts 34, 35, 86, 37 to disconnect the detector from the receiving circuit in order to prevent injury thereto; (6) the member 25 short circuits the contacts 26 and 27, thus short circuiting the receiving circuit 9, 10; (c) the movable contacts 18 on the rod 17 open the spark gaps 16 and remove the short circuit around the transmitting coil 3; ((Z) movement of contact 23 against contact 24 closes the circuit of the generator l to supply potential for charging the quenched spark gap 6 which discharges through the oscillatory circuit 7, 8 which is coupled to the coil 3 which supplies current for the antenna circuit 1, 3,26, 25, 2.

A single interrupter may be utilized, but a given number of interrupters have a greater breakdown voltage than a single interrupter whose gap is equal to the combined length of the series gaps and furthermore a shorter movement of the armature is sufficient to remove the short circuit around the transmitting inductance.

Having described my invention, what I claim is:

1. In radio signaling apparatus, the combination of an antenna, a transmitting inductance permanently connected therein, a receiving inductance also permanently connected therein, a plurality of interrupters connected in series across said transmitting inductance for opening and closing a shortcircuiting path around said inductance, an interrupter for opening and closing a shortoircuiting path around said receiving in.- ductance, a single means for operating said group of interrupters and said interrupter and normally mantaining a short-circuit around said transn'iitting inductance, and an open circuit around said receiving inductance, a transmitting key and means operating synchronously with said transmitting key for operating said single means to operate all of said interrupters to open said v short-circuiting path around said transmitting inductance and to short-circuit said receiving inductance.

2. In radio signaling apparatus adapted to operate either for transmission or reception, the combination of an antenna, a transmitting inductance adapted to carry transmission energy, a plurality of interrupters connected in series across said transmitting inductance and adapted when closed to short-circuit the same and a single means for operating all of said interrupters simultaneously and in synchronism with keying, whereby the breakdown voltage across said l11tQ-l'l'll] ')t(1 is relatively great and a shorter movement of interrupter contacts is suflicient to remove the short-circuit around said transmitting inductance.

3. In radio signaling apparatus adapted for either transmission or reception, the combination of an antenna, a transmitting inductance in said antenna, a plurality of stationary contacts, alternate of said contacts being connected together to define a plurality of gaps, the first and last contacts of said group being connected to the ends of the transmitting inductance respectively, a slidable armature having contacts cooperating with said stationary contacts for completing a short-circuiting path around said inductance and means operable synchronously with keying for causing said armature to move longitudinally t0 circuit-closing position, whereby a greater break-down voltage across said path is obtainable than that ohtainable with a single interrupter and whereby shorter movement of said armature is sufiicient to remove the short circuit around said transmitting inductance.

4. In radio signal apparatus, a combination of an antenna circuit, a transmitting inductance and a receiving inductance permanently connected in said circuit, an interrupter arranged to normally short circuit said transmitting inductance, means normal- 1y inoperative to short circuit said receiving inductance, a single means to render said interruptor inoperative as a short circuit for said transmitting inductance and simultaneously to render the receiving inductance short circuiting means operative, whereby the apparatus is changed from a receiving to a transmitting system, a receiving circuit coupled to said receiving inductance, said receiving circuit including a detector, and. means governed by said single means to control the operation of the detector.

5. In radio signaling apparatus, the combination of an antenna, a transmitting inductance permanently connected therein, a

receiving inductance also permanently connected therein, a plurality of lnterruptors connected in series across said transmitting ynductance for opening and closing a short oircuiting path around said inductance, an 

